Description

The divisors of a natural number are all the natural numbers that can divide it without leaving a remainder. For example, the divisors of 6 are: 1, 2, 3, 6. Now, given a number n, find the smallest positive integer whose sum of divisors equals n (if no such number exists, output -1).

Input Format

A number n (1 <= n <= 1000000)

Output Format

A number a

```input1 6 ``` ```output1 5 ``` ## 来源

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